Heat-storing firebricks can provide the heat we get from fossil fuels

Scientists at Stanford University’s Department of Civil and Environmental Engineering have reached back into the past for inspiration to potentially offer a life-saving solution we’ll need in the near future: using firebricks, a technology used by humanity since the Bronze Age, to store heat from renewable sources and then release that heat in industrial environments where certain manufacturing processes require high temperatures.

Stanford researchers have produced a new paper showing that firebrick technology could be an affordable, yet environmentally friendly solution for factories that produce cement, glass, steel and other high-temperature products.

Instead of burning fossil fuels to reach desired temperatures, factories will store heat much like batteries store energy. The heat will come from renewable sources, such as sun and wind, with some obvious advantages.

By using firebricks, factories could operate even when there is no direct access to solar or wind energy, reducing the need to use batteries to store energy from the same sources.

Overall, this process will reduce the carbon footprint of these companies, enabling them to continue operating into a future where net zero emissions will be a priority for most countries.

The United Nations is aiming to achieve net zero emissions by 2050, and Stanford researchers believe that advanced firebricks can help achieve that. According to Stanford ReportAbout 17% of the world’s CO2 emissions come from burning fossil fuels to produce heat for industries. The data comes from calculations by one of the authors of the new study. Firebricks could eliminate these emissions.

As the name suggests, firebricks can absorb heat when they are built into an insulated container. They release heat only when air flows through channels placed in stacks of firebricks.

The researchers explain that the firebricks are made “from the same materials as the insulating bricks that lined the original iron-making furnaces and ovens thousands of years ago.” The only difference is that they would be optimized for heat storage rather than insulation.

The firebricks would then release the high-temperature heat needed by various industries. Cement needs 1,300 degrees Celsius (almost 2,400 degrees Fahrenheit). The temperature requirements of glass, iron, and steel are slightly lower, at over 1,000 C (about 1,800 F).

Stanford researchers created a computer model that compared two scenarios for 2050 and beyond. In one scenario, 149 countries responsible for 99.75% of global CO2 emissions from fossil fuels used firebricks to provide 90% of the heat for industrial processes.

In the second scenario, factories used different methods of generating heat from renewable energy. These included electric furnaces, boilers, heat pumps and batteries.

The researchers calculated that for 149 countries, using heat storage technology in the form of firebricks would be $1.27 trillion cheaper than using some form of electricity to produce heat.

Computer models compared costs, land requirements, health impacts and emissions for both scenarios. Since air pollution from fossil fuels causes millions of premature deaths each year, firebricks could also help improve overall health by significantly reducing emissions.

The researchers believe their solution can work on the projected scale due to the obvious cost savings.

“Imagine proposing an expensive and difficult way to switch to renewable electricity — we would get very few takers. But if it saves money over the previous method, it will be implemented more quickly,” lead study author Mark Z. Jacobson said in a statement.

“What excites me is that the impact is very large, whereas many technologies I’ve studied have marginal impact. Here I see a significant benefit at low cost on many fronts, from helping reduce air pollution mortality to facilitating the world’s transition to clean, renewable energy sources.”

“The difference between firebrick storage and battery storage is that firebricks store heat, not electricity, and they cost one-tenth of the cost of batteries,” he said. The materials are also much simpler. They’re basically just dirt.

The full study is available at Nexus PNAS.